git.sesse.net Git - nageru/blob - alsa_pool.cpp

   1 #include "alsa_pool.h"
   2
   3 #include <alsa/control.h>
   4 #include <alsa/error.h>
   5 #include <alsa/pcm.h>
   6 #include <assert.h>
   7 #include <limits.h>
   8 #include <stdio.h>
   9 #include <sys/inotify.h>
  10 #include <unistd.h>
  11 #include <algorithm>
  12 #include <memory>
  13
  14 #include "alsa_input.h"
  15 #include "audio_mixer.h"
  16 #include "defs.h"
  17 #include "input_mapping.h"
  18 #include "state.pb.h"
  19
  20 using namespace std;
  21 using namespace std::placeholders;
  22
  23 ALSAPool::~ALSAPool()
  24 {
  25         for (Device &device : devices) {
  26                 if (device.input != nullptr) {
  27                         device.input->stop_capture_thread();
  28                 }
  29         }
  30         should_quit = true;
  31         inotify_thread.join();
  32 }
  33
  34 std::vector<ALSAPool::Device> ALSAPool::get_devices()
  35 {
  36         lock_guard<mutex> lock(mu);
  37         for (Device &device : devices) {
  38                 device.held = true;
  39         }
  40         return devices;
  41 }
  42
  43 void ALSAPool::hold_device(unsigned index)
  44 {
  45         lock_guard<mutex> lock(mu);
  46         assert(index < devices.size());
  47         devices[index].held = true;
  48 }
  49
  50 void ALSAPool::release_device(unsigned index)
  51 {
  52         lock_guard<mutex> lock(mu);
  53         if (index < devices.size()) {
  54                 devices[index].held = false;
  55         }
  56 }
  57
  58 void ALSAPool::enumerate_devices()
  59 {
  60         // Enumerate all cards.
  61         for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
  62                 char address[256];
  63                 snprintf(address, sizeof(address), "hw:%d", card_index);
  64
  65                 snd_ctl_t *ctl;
  66                 int err = snd_ctl_open(&ctl, address, 0);
  67                 if (err < 0) {
  68                         printf("%s: %s\n", address, snd_strerror(err));
  69                         continue;
  70                 }
  71                 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
  72
  73                 // Enumerate all devices on this card.
  74                 for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
  75                         probe_device_with_retry(card_index, dev_index);
  76                 }
  77         }
  78 }
  79
  80 void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
  81 {
  82         char address[256];
  83         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
  84
  85         lock_guard<mutex> lock(add_device_mutex);
  86         if (add_device_tries_left.count(address)) {
  87                 // Some thread is already busy retrying this,
  88                 // so just reset its count.
  89                 add_device_tries_left[address] = num_retries;
  90                 return;
  91         }
  92
  93         // Try (while still holding the lock) to add the device synchronously.
  94         ProbeResult result = probe_device_once(card_index, dev_index);
  95         if (result == ProbeResult::SUCCESS) {
  96                 return;
  97         } else if (result == ProbeResult::FAILURE) {
  98                 return;
  99         }
 100         assert(result == ProbeResult::DEFER);
 101
 102         // Add failed for whatever reason (probably just that the device
 103         // isn't up yet. Set up a count so that nobody else starts a thread,
 104         // then start it ourselves.
 105         fprintf(stderr, "Trying %s again in one second...\n", address);
 106         add_device_tries_left[address] = num_retries;
 107         thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
 108 }
 109
 110 void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
 111 {
 112         char address[256];
 113         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 114
 115         for ( ;; ) {  // Termination condition within the loop.
 116                 sleep(1);
 117
 118                 // See if there are any retries left.
 119                 lock_guard<mutex> lock(add_device_mutex);
 120                 if (!add_device_tries_left.count(address) ||
 121                     add_device_tries_left[address] == 0) {
 122                         add_device_tries_left.erase(address);
 123                         fprintf(stderr, "Giving up probe of %s.\n", address);
 124                         return;
 125                 }
 126
 127                 // Seemingly there were. Give it a try (we still hold the mutex).
 128                 ProbeResult result = probe_device_once(card_index, dev_index);
 129                 if (result == ProbeResult::SUCCESS) {
 130                         add_device_tries_left.erase(address);
 131                         fprintf(stderr, "Probe of %s succeeded.\n", address);
 132                         return;
 133                 } else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
 134                         add_device_tries_left.erase(address);
 135                         fprintf(stderr, "Giving up probe of %s.\n", address);
 136                         return;
 137                 }
 138
 139                 // Failed again.
 140                 assert(result == ProbeResult::DEFER);
 141                 fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
 142                         address, add_device_tries_left[address]);
 143         }
 144 }
 145
 146 ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
 147 {
 148         char address[256];
 149         snprintf(address, sizeof(address), "hw:%d", card_index);
 150         snd_ctl_t *ctl;
 151         int err = snd_ctl_open(&ctl, address, 0);
 152         if (err < 0) {
 153                 printf("%s: %s\n", address, snd_strerror(err));
 154                 return ALSAPool::ProbeResult::DEFER;
 155         }
 156         unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 157
 158         snd_pcm_info_t *pcm_info;
 159         snd_pcm_info_alloca(&pcm_info);
 160         snd_pcm_info_set_device(pcm_info, dev_index);
 161         snd_pcm_info_set_subdevice(pcm_info, 0);
 162         snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
 163         if (snd_ctl_pcm_info(ctl, pcm_info) < 0) {
 164                 // Not available for capture.
 165                 printf("%s: Not available for capture.\n", address);
 166                 return ALSAPool::ProbeResult::DEFER;
 167         }
 168
 169         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 170
 171         unsigned num_channels = 0;
 172
 173         // Find all channel maps for this device, and pick out the one
 174         // with the most channels.
 175         snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
 176         if (cmaps != nullptr) {
 177                 for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
 178                         num_channels = max(num_channels, (*ptr)->map.channels);
 179                 }
 180                 snd_pcm_free_chmaps(cmaps);
 181         }
 182         if (num_channels == 0) {
 183                 // Device had no channel maps. We need to open it to query.
 184                 // TODO: Do this asynchronously.
 185                 snd_pcm_t *pcm_handle;
 186                 int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
 187                 if (err < 0) {
 188                         printf("%s: %s\n", address, snd_strerror(err));
 189                         return ALSAPool::ProbeResult::DEFER;
 190                 }
 191                 snd_pcm_hw_params_t *hw_params;
 192                 snd_pcm_hw_params_alloca(&hw_params);
 193                 unsigned sample_rate;
 194                 if (!ALSAInput::set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
 195                         snd_pcm_close(pcm_handle);
 196                         return ALSAPool::ProbeResult::DEFER;
 197                 }
 198                 err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
 199                 if (err < 0) {
 200                         fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
 201                                 address, snd_strerror(err));
 202                         snd_pcm_close(pcm_handle);
 203                         return ALSAPool::ProbeResult::DEFER;
 204                 }
 205                 snd_pcm_close(pcm_handle);
 206         }
 207
 208         if (num_channels == 0) {
 209                 printf("%s: No channel maps with channels\n", address);
 210                 return ALSAPool::ProbeResult::FAILURE;
 211         }
 212
 213         snd_ctl_card_info_t *card_info;
 214         snd_ctl_card_info_alloca(&card_info);
 215         snd_ctl_card_info(ctl, card_info);
 216
 217         string name = snd_ctl_card_info_get_name(card_info);
 218         string info = snd_pcm_info_get_name(pcm_info);
 219
 220         unsigned internal_dev_index;
 221         string display_name;
 222         {
 223                 lock_guard<mutex> lock(mu);
 224                 internal_dev_index = find_free_device_index(name, info, num_channels, address);
 225                 devices[internal_dev_index].address = address;
 226                 devices[internal_dev_index].name = name;
 227                 devices[internal_dev_index].info = info;
 228                 devices[internal_dev_index].num_channels = num_channels;
 229                 // Note: Purposefully does not overwrite held.
 230
 231                 display_name = devices[internal_dev_index].display_name();
 232         }
 233
 234         fprintf(stderr, "%s: Probed successfully.\n", address);
 235
 236         reset_device(internal_dev_index);  // Restarts it if it is held (ie., we just replaced a dead card).
 237
 238         DeviceSpec spec{InputSourceType::ALSA_INPUT, internal_dev_index};
 239         global_audio_mixer->set_display_name(spec, display_name);
 240         global_audio_mixer->trigger_state_changed_callback();
 241
 242         return ALSAPool::ProbeResult::SUCCESS;
 243 }
 244
 245 void ALSAPool::unplug_device(unsigned card_index, unsigned dev_index)
 246 {
 247         char address[256];
 248         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 249         for (unsigned i = 0; i < devices.size(); ++i) {
 250                 if (devices[i].state != Device::State::EMPTY &&
 251                     devices[i].state != Device::State::DEAD &&
 252                     devices[i].address == address) {
 253                         free_card(i);
 254                 }
 255         }
 256 }
 257
 258 void ALSAPool::init()
 259 {
 260         inotify_thread = thread(&ALSAPool::inotify_thread_func, this);
 261         enumerate_devices();
 262 }
 263
 264 void ALSAPool::inotify_thread_func()
 265 {
 266         int inotify_fd = inotify_init();
 267         if (inotify_fd == -1) {
 268                 perror("inotify_init()");
 269                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 270                 return;
 271         }
 272
 273         int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
 274         if (watch_fd == -1) {
 275                 perror("inotify_add_watch()");
 276                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 277                 close(inotify_fd);
 278                 return;
 279         }
 280
 281         int size = sizeof(inotify_event) + NAME_MAX + 1;
 282         unique_ptr<char[]> buf(new char[size]);
 283         while (!should_quit) {
 284                 pollfd fds;
 285                 fds.fd = inotify_fd;
 286                 fds.events = POLLIN;
 287                 fds.revents = 0;
 288
 289                 int ret = poll(&fds, 1, 100);
 290                 if (ret == -1) {
 291                         if (errno == EINTR) {
 292                                 continue;
 293                         } else {
 294                                 perror("poll(inotify_fd)");
 295                                 return;
 296                         }
 297                 }
 298                 if (ret == 0) {
 299                         continue;
 300                 }
 301
 302                 ret = read(inotify_fd, buf.get(), size);
 303                 if (ret == -1) {
 304                         if (errno == EINTR) {
 305                                 continue;
 306                         } else {
 307                                 perror("read(inotify_fd)");
 308                                 close(watch_fd);
 309                                 close(inotify_fd);
 310                                 return;
 311                         }
 312                 }
 313                 if (ret < int(sizeof(inotify_event))) {
 314                         fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
 315                                 int(ret));
 316                         close(watch_fd);
 317                         close(inotify_fd);
 318                         return;
 319                 }
 320
 321                 for (int i = 0; i < ret; ) {
 322                         const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
 323                         i += sizeof(inotify_event) + event->len;
 324
 325                         if (event->mask & IN_Q_OVERFLOW) {
 326                                 fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
 327                                 continue;
 328                         }
 329                         unsigned card, device;
 330                         char type;
 331                         if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
 332                                 if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
 333                                         printf("Deleted capture device: Card %u, device %u\n", card, device);
 334                                         unplug_device(card, device);
 335                                 }
 336                                 if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
 337                                         printf("Adding capture device: Card %u, device %u\n", card, device);
 338                                         probe_device_with_retry(card, device);
 339                                 }
 340                         }
 341                 }
 342         }
 343         close(watch_fd);
 344         close(inotify_fd);
 345 }
 346
 347 void ALSAPool::reset_device(unsigned index)
 348 {
 349         lock_guard<mutex> lock(mu);
 350         Device *device = &devices[index];
 351         if (inputs[index] != nullptr) {
 352                 inputs[index]->stop_capture_thread();
 353         }
 354         if (!device->held) {
 355                 inputs[index].reset();
 356         } else {
 357                 // TODO: Put on a background thread instead of locking?
 358                 auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4);
 359                 inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
 360                 inputs[index]->start_capture_thread();
 361         }
 362         device->input = inputs[index].get();
 363 }
 364
 365 unsigned ALSAPool::get_capture_frequency(unsigned index)
 366 {
 367         lock_guard<mutex> lock(mu);
 368         assert(devices[index].held);
 369         if (devices[index].input)
 370                 return devices[index].input->get_sample_rate();
 371         else
 372                 return OUTPUT_FREQUENCY;
 373 }
 374
 375 ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
 376 {
 377         lock_guard<mutex> lock(mu);
 378         assert(devices[index].held);
 379         return devices[index].state;
 380 }
 381
 382 void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
 383 {
 384         {
 385                 lock_guard<mutex> lock(mu);
 386                 devices[index].state = state;
 387         }
 388
 389         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 390         bool silence = (state != ALSAPool::Device::State::RUNNING);
 391         while (!global_audio_mixer->silence_card(spec, silence))
 392                 ;
 393         global_audio_mixer->trigger_state_changed_callback();
 394 }
 395
 396 unsigned ALSAPool::find_free_device_index(const string &name, const string &info, unsigned num_channels, const string &address)
 397 {
 398         // First try to find an exact match on a dead card.
 399         for (unsigned i = 0; i < devices.size(); ++i) {
 400                 if (devices[i].state == Device::State::DEAD &&
 401                     devices[i].address == address &&
 402                     devices[i].name == name &&
 403                     devices[i].info == info &&
 404                     devices[i].num_channels == num_channels) {
 405                         devices[i].state = Device::State::READY;
 406                         return i;
 407                 }
 408         }
 409
 410         // Then try to find a match on everything but the address
 411         // (probably that devices were plugged back in a different order).
 412         // If we have two cards that are equal, this might get them mixed up,
 413         // but we don't have anything better.
 414         for (unsigned i = 0; i < devices.size(); ++i) {
 415                 if (devices[i].state == Device::State::DEAD &&
 416                     devices[i].name == name &&
 417                     devices[i].info == info &&
 418                     devices[i].num_channels == num_channels) {
 419                         devices[i].state = Device::State::READY;
 420                         return i;
 421                 }
 422         }
 423
 424         // OK, so we didn't find a match; see if there are any empty slots.
 425         for (unsigned i = 0; i < devices.size(); ++i) {
 426                 if (devices[i].state == Device::State::EMPTY) {
 427                         devices[i].state = Device::State::READY;
 428                         devices[i].held = false;
 429                         return i;
 430                 }
 431         }
 432
 433         // Failing that, we just insert the new device at the end.
 434         Device new_dev;
 435         new_dev.state = Device::State::READY;
 436         new_dev.held = false;
 437         devices.push_back(new_dev);
 438         inputs.emplace_back(nullptr);
 439         return devices.size() - 1;
 440 }
 441
 442 unsigned ALSAPool::create_dead_card(const string &name, const string &info, unsigned num_channels)
 443 {
 444         lock_guard<mutex> lock(mu);
 445
 446         // See if there are any empty slots. If not, insert one at the end.
 447         vector<Device>::iterator free_device =
 448                 find_if(devices.begin(), devices.end(),
 449                         [](const Device &device) { return device.state == Device::State::EMPTY; });
 450         if (free_device == devices.end()) {
 451                 devices.push_back(Device());
 452                 inputs.emplace_back(nullptr);
 453                 free_device = devices.end() - 1;
 454         }
 455
 456         free_device->state = Device::State::DEAD;
 457         free_device->name = name;
 458         free_device->info = info;
 459         free_device->num_channels = num_channels;
 460         free_device->held = true;
 461
 462         return distance(devices.begin(), free_device);
 463 }
 464
 465 void ALSAPool::serialize_device(unsigned index, DeviceSpecProto *serialized)
 466 {
 467         lock_guard<mutex> lock(mu);
 468         assert(index < devices.size());
 469         assert(devices[index].held);
 470         serialized->set_type(DeviceSpecProto::ALSA_INPUT);
 471         serialized->set_index(index);
 472         serialized->set_display_name(devices[index].display_name());
 473         serialized->set_alsa_name(devices[index].name);
 474         serialized->set_alsa_info(devices[index].info);
 475         serialized->set_num_channels(devices[index].num_channels);
 476         serialized->set_address(devices[index].address);
 477 }
 478
 479 void ALSAPool::free_card(unsigned index)
 480 {
 481         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 482         while (!global_audio_mixer->silence_card(spec, true))
 483                 ;
 484
 485         {
 486                 lock_guard<mutex> lock(mu);
 487                 if (devices[index].held) {
 488                         devices[index].state = Device::State::DEAD;
 489                 } else {
 490                         devices[index].state = Device::State::EMPTY;
 491                         inputs[index].reset();
 492                 }
 493                 while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
 494                         devices.pop_back();
 495                         inputs.pop_back();
 496                 }
 497         }
 498
 499         global_audio_mixer->trigger_state_changed_callback();
 500 }