pipewire/spa/plugins/alsa/alsa-monitor.c

/* Spa ALSA Monitor
 * Copyright (C) 2016 Wim Taymans <wim.taymans@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include <stddef.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <poll.h>

#include <libudev.h>

#include <spa/poll.h>
#include <spa/monitor.h>
#include <spa/memory.h>
#include <spa/debug.h>

extern const SpaHandleFactory spa_alsa_source_factory;

typedef struct _SpaALSAMonitor SpaALSAMonitor;

typedef struct {
  SpaMonitorItem item;
  struct udev_device *udevice;
  SpaDict     info;
  SpaDictItem info_items[32];
} ALSAItem;

struct _SpaALSAMonitor {
  SpaHandle handle;
  SpaMonitor monitor;

  SpaMonitorEventCallback event_cb;
  void *user_data;

  struct udev* udev;
  struct udev_monitor *umonitor;
  struct udev_enumerate *enumerate;

  ALSAItem uitem;

  int fd;
  SpaPollFd fds[1];
  SpaPollItem poll;
};

static SpaResult
alsa_udev_open (SpaALSAMonitor *this)
{
  if (this->udev != NULL)
    return SPA_RESULT_OK;

  this->udev = udev_new ();

  return SPA_RESULT_OK;
}

static const char *
path_get_card_id (const char *path)
{
  const char *e;

  if (!path)
    return NULL;

  if (!(e = strrchr(path, '/')))
    return NULL;

  if (strlen (e) <= 5 || strncmp (e, "/card", 5) != 0)
    return NULL;

  return e + 5;
}

static int
fill_item (ALSAItem *item, struct udev_device *udevice)
{
  unsigned int i;
  const char *str;

  if (item->udevice)
    udev_device_unref (item->udevice);
  item->udevice = udevice;
  if (udevice == NULL)
    return -1;

  if (udev_device_get_property_value (udevice, "PULSE_IGNORE"))
    return -1;

  if ((str = udev_device_get_property_value (udevice, "SOUND_CLASS")) &&
      strcmp (str, "modem") == 0)
    return -1;

  if ((str = path_get_card_id (udev_device_get_property_value (udevice, "DEVPATH"))) == NULL)
    return -1;

  item->item.id = udev_device_get_syspath (item->udevice);
  item->item.flags = 0;
  item->item.state = SPA_MONITOR_ITEM_STATE_AVAILABLE;
  item->item.klass = "Audio/Device";
  item->item.info = &item->info;
  item->item.factory = &spa_alsa_source_factory;

  item->info.items = item->info_items;
  i = 0;
  item->info_items[i].key = "alsa.card";
  item->info_items[i++].value = str;
  item->info_items[i].key = "udev-probed";
  item->info_items[i++].value = "1";
  item->info_items[i].key = "device.api";
  item->info_items[i++].value = "alsa";

  if ((str = udev_device_get_property_value (udevice, "SOUND_CLASS")) && *str) {
    item->info_items[i].key = "device.class";
    item->info_items[i++].value = str;
  }

  str = udev_device_get_property_value (item->udevice, "ID_PATH");
  if (!(str && *str))
    str = udev_device_get_syspath (item->udevice);
  if (str && *str) {
    item->info_items[i].key = "device.bus_path";
    item->info_items[i++].value = str;
  }
  if ((str = udev_device_get_syspath (item->udevice)) && *str) {
    item->info_items[i].key = "sysfs.path";
    item->info_items[i++].value = str;
  }
  if ((str = udev_device_get_property_value (item->udevice, "ID_ID")) && *str) {
    item->info_items[i].key = "udev.id";
    item->info_items[i++].value = str;
  }
  if ((str = udev_device_get_property_value (item->udevice, "ID_BUS")) && *str) {
    item->info_items[i].key = "device.bus";
    item->info_items[i++].value = str;
  }
  if ((str = udev_device_get_property_value (item->udevice, "SUBSYSTEM")) && *str) {
    item->info_items[i].key = "device.subsystem";
    item->info_items[i++].value = str;
  }
  if ((str = udev_device_get_property_value (item->udevice, "ID_VENDOR_ID")) && *str) {
    item->info_items[i].key = "device.vendor.id";
    item->info_items[i++].value = str;
  }
  str = udev_device_get_property_value (item->udevice, "ID_VENDOR_FROM_DATABASE");
  if (!(str && *str)) {
    str = udev_device_get_property_value (item->udevice, "ID_VENDOR_ENC");
    if (!(str && *str)) {
      str = udev_device_get_property_value (item->udevice, "ID_VENDOR");
    }
  }
  if (str && *str) {
    item->info_items[i].key = "device.vendor.name";
    item->info_items[i++].value = str;
  }
  if ((str = udev_device_get_property_value (item->udevice, "ID_MODEL_ID")) && *str) {
    item->info_items[i].key = "device.product.id";
    item->info_items[i++].value = str;
  }
  str = udev_device_get_property_value (item->udevice, "ID_MODEL_FROM_DATABASE");
  if (!(str && *str)) {
    str = udev_device_get_property_value (item->udevice, "ID_MODEL_ENC");
    if (!(str && *str)) {
      str = udev_device_get_property_value (item->udevice, "ID_MODEL");
    }
  }
  if (str && *str) {
    item->info_items[i].key = "device.product.name";
    item->info_items[i++].value = str;
    item->item.name = str;
  } else {
    item->item.name = "Unknown";
  }
  if ((str = udev_device_get_property_value (item->udevice, "ID_SERIAL")) && *str) {
    item->info_items[i].key = "device.serial";
    item->info_items[i++].value = str;
  }
  if ((str = udev_device_get_property_value (item->udevice, "SOUND_FORM_FACTOR")) && *str) {
    item->info_items[i].key = "device.form_factor";
    item->info_items[i++].value = str;
  }
  item->info.n_items = i;

  return 0;
}

static int
alsa_on_fd_events (SpaPollNotifyData *data)
{
  SpaALSAMonitor *this = data->user_data;
  struct udev_device *dev;
  const char *str;
  SpaMonitorEvent event;

  dev = udev_monitor_receive_device (this->umonitor);
  if (fill_item (&this->uitem, dev) < 0)
    return 0;

  if ((str = udev_device_get_action (dev)) == NULL)
    str = "change";

  if (strcmp (str, "add") == 0) {
    event.type = SPA_MONITOR_EVENT_TYPE_ADDED;
  } else if (strcmp (str, "change") == 0) {
    event.type = SPA_MONITOR_EVENT_TYPE_CHANGED;
  } else if (strcmp (str, "remove") == 0) {
    event.type = SPA_MONITOR_EVENT_TYPE_REMOVED;
  }
  event.data = &this->uitem.item;
  event.size = sizeof (this->uitem);
  this->event_cb (&this->monitor, &event, this->user_data);

  return 0;
}

static SpaResult
spa_alsa_monitor_set_event_callback (SpaMonitor              *monitor,
                                     SpaMonitorEventCallback  callback,
                                     void                    *user_data)
{
  SpaResult res;
  SpaALSAMonitor *this;
  SpaMonitorEvent event;

  if (monitor == NULL || monitor->handle == NULL)
    return SPA_RESULT_INVALID_ARGUMENTS;

  this = (SpaALSAMonitor *) monitor->handle;

  this->event_cb = callback;
  this->user_data = user_data;

  if (callback) {
    if ((res = alsa_udev_open (this)) < 0)
      return res;

    this->umonitor = udev_monitor_new_from_netlink (this->udev, "udev");
    if (!this->umonitor)
      return SPA_RESULT_ERROR;

    udev_monitor_filter_add_match_subsystem_devtype (this->umonitor,
                                                     "video4linux",
                                                     NULL);

    udev_monitor_enable_receiving (this->umonitor);
    this->fd = udev_monitor_get_fd (this->umonitor);;

    event.type = SPA_MONITOR_EVENT_TYPE_ADD_POLL;
    event.data = &this->poll;
    event.size = sizeof (this->poll);

    this->fds[0].fd = this->fd;
    this->fds[0].events = POLLIN | POLLPRI | POLLERR;
    this->fds[0].revents = 0;

    this->poll.id = 0;
    this->poll.enabled = true;
    this->poll.fds = this->fds;
    this->poll.n_fds = 1;
    this->poll.idle_cb = NULL;
    this->poll.before_cb = NULL;
    this->poll.after_cb = alsa_on_fd_events;
    this->poll.user_data = this;
    this->event_cb (&this->monitor, &event, this->user_data);
  } else {
    event.type = SPA_MONITOR_EVENT_TYPE_REMOVE_POLL;
    event.data = &this->poll;
    event.size = sizeof (this->poll);
    this->event_cb (&this->monitor, &event, this->user_data);
  }

  return SPA_RESULT_OK;
}

static SpaResult
spa_alsa_monitor_enum_items (SpaMonitor       *monitor,
                             SpaMonitorItem  **item,
                             void            **state)
{
  SpaResult res;
  SpaALSAMonitor *this;
  struct udev_list_entry *devices;
  struct udev_device *dev;

  if (monitor == NULL || monitor->handle == NULL || item == NULL || state == NULL)
    return SPA_RESULT_INVALID_ARGUMENTS;

  this = (SpaALSAMonitor *) monitor->handle;

  if ((res = alsa_udev_open (this)) < 0)
    return res;

again:
  if (*state == NULL) {
    if (this->enumerate)
      udev_enumerate_unref (this->enumerate);
    this->enumerate = udev_enumerate_new (this->udev);

    udev_enumerate_add_match_subsystem (this->enumerate, "sound");
    udev_enumerate_scan_devices (this->enumerate);

    devices = udev_enumerate_get_list_entry (this->enumerate);
    if (devices == NULL)
      return SPA_RESULT_ENUM_END;
  } else {
    devices = *state;
  }

  if (*state == (void*)1) {
    fill_item (&this->uitem, NULL);
    return SPA_RESULT_ENUM_END;
  }

  dev = udev_device_new_from_syspath (this->udev,
                                      udev_list_entry_get_name (devices));

  if ((*state = udev_list_entry_get_next (devices)) == NULL)
    *state = (void*)1;

  if (fill_item (&this->uitem, dev) < 0)
    goto again;

  *item = &this->uitem.item;

  return SPA_RESULT_OK;
}

static const SpaMonitor alsamonitor = {
  NULL,
  NULL,
  sizeof (SpaMonitor),
  spa_alsa_monitor_set_event_callback,
  spa_alsa_monitor_enum_items,
};

static SpaResult
spa_alsa_monitor_get_interface (SpaHandle               *handle,
                                uint32_t                 interface_id,
                                void                   **interface)
{
  SpaALSAMonitor *this;

  if (handle == NULL || interface == NULL)
    return SPA_RESULT_INVALID_ARGUMENTS;

  this = (SpaALSAMonitor *) handle;

  switch (interface_id) {
    case SPA_INTERFACE_ID_MONITOR:
      *interface = &this->monitor;
      break;
    default:
      return SPA_RESULT_UNKNOWN_INTERFACE;
  }
  return SPA_RESULT_OK;
}

static SpaResult
alsa_monitor_clear (SpaHandle *handle)
{
  return SPA_RESULT_OK;
}

static SpaResult
alsa_monitor_init (const SpaHandleFactory  *factory,
                   SpaHandle               *handle,
                   const SpaDict           *info)
{
  SpaALSAMonitor *this;

  if (factory == NULL || handle == NULL)
    return SPA_RESULT_INVALID_ARGUMENTS;

  handle->get_interface = spa_alsa_monitor_get_interface;
  handle->clear = alsa_monitor_clear,

  this = (SpaALSAMonitor *) handle;
  this->monitor = alsamonitor;
  this->monitor.handle = handle;

  return SPA_RESULT_OK;
}

static const SpaInterfaceInfo alsa_monitor_interfaces[] =
{
  { SPA_INTERFACE_ID_MONITOR,
    SPA_INTERFACE_ID_MONITOR_NAME,
    SPA_INTERFACE_ID_MONITOR_DESCRIPTION,
  },
};

static SpaResult
alsa_monitor_enum_interface_info (const SpaHandleFactory  *factory,
                                  const SpaInterfaceInfo **info,
                                  void                   **state)
{
  int index;

  if (factory == NULL || info == NULL || state == NULL)
    return SPA_RESULT_INVALID_ARGUMENTS;

  index = (*state == NULL ? 0 : *(int*)state);

  if (index < 0 || index >= SPA_N_ELEMENTS (alsa_monitor_interfaces))
    return SPA_RESULT_ENUM_END;

  *info = &alsa_monitor_interfaces[index];
  *(int*)state = ++index;
  return SPA_RESULT_OK;
}

const SpaHandleFactory spa_alsa_monitor_factory =
{ "alsa-monitor",
  NULL,
  sizeof (SpaALSAMonitor),
  alsa_monitor_init,
  alsa_monitor_enum_interface_info,
};